However, a new app called Sync Solver for Fitbit has appeared on the App Store offering the service that neither Apple nor Fitbit want to provide on their own. The app will let you sync ten different pieces of data from your Fitbit Flex or Fitbit Charge, including the usual steps, calories and distance.

Unfortunately, the developer warns that there's no way to disable step counting from the iPhone itself, so you're likely to see twice as many steps as you've taken because it's being measured by both the handset and the Fitbit.